The March 2000 issue of The Physics Teacher contains the note "A
Consistent Sign Convention for Work," by The Advanced Placement (AP)
Physics Development Committee. Beginning May 2002, the sign convention
for work on AP exams in the context of the first law of thermodynamics
will be reversed. At present, the convention used is that work done by
the system is positive. That will be changed to work done on the system
being positive.
The authors indicate the principal force driving this change is that
chemistry books use work done on the system as positive, so it would be
less confusing to students if physics did the same. It seems a given
that future revisions of general physics textbooks will adopt the AP
convention.
While the note discusses conventions in the chemistry and physics
communities, it does not mention the engineering communities. I checked
an engineering thermodynamics textbook (Cengel and Boles, 1989) and
found they use the same convention that the physics community now uses
-- work done by the system is positive. It seems likely that other
engineering thermo texts also follow this convention.
Should we adopt the chemistry convention or stick with the
physics-engineering convention? It appears this decision is being made
by the AP Physics Development Committee. Any comments?